I’ve noticed that, besides the magnetism and drive for sex (which would be sufficient for a species to propagate), many people also experience the biological imperative (wanting their genes replicated) as its own separate feeling.
This makes no sense to me – it’s not a feeling I can personally relate to. I’d like to raise kids because I’d enjoy getting to teach them and share things with them, but I don’t care whether they are my biological children or not.
So it’s something I’ve wondered about. The likely why makes sense, but I don’t really get the what.